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How do I force the column alias to be of specific data type in MySQL?
For this, you can use CASE statement. Let us first create a table −
mysql> create table DemoTable1505 -> ( -> Value integer unsigned, -> Status tinyint(1) -> ); Query OK, 0 rows affected (0.47 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable1505 values(20,0); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable1505 values(45,1); Query OK, 1 row affected (0.08 sec)
Display all records from the table using select statement −
mysql> select * from DemoTable1505;
This will produce the following output −
+-------+--------+ | Value | Status | +-------+--------+ | 20 | 0 | | 45 | 1 | +-------+--------+ 2 rows in set (0.00 sec)
Here is the query to force the column alias to be of specific data type −
mysql> select case status -> when 0 then cast(Value as signed)*1 -> when 1 then cast(Value as signed)*-1 -> end as AllValues from DemoTable1505;
This will produce the following output −
+-----------+ | AllValues | +-----------+ | 20 | | -45 | +-----------+ 2 rows in set (0.00 sec)
Updated on: 11-Dec-2019
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